source: http://www.securityfocus.com/bid/31855/info

Mozilla Firefox 3 is prone to a cross-site scripting weakness that arises because the software fails to handle specially crafted files served using the FTP protocol.

Successfully exploiting this issue may allow an attacker to execute arbitrary script code in the browser of an unsuspecting user in the context of an FTP session. This may allow the attacker to perform malicious actions in a user's browser or redirect the user to a malicious site; other attacks are also possible. 

<html>
<body>
<script>alert('backdoored');</script>
</body>
</html>

